The present invention relates to a digital audio/video (A/V) apparatus, and more particularly, to a multi-media system in which a plurality of digital A/V devices are connected each other via a digital interface.
In a digital A/V apparatus, a device can be controlled by other devices, which could not be achieved in a conventional analog A/V apparatus. As an example, the High-Definition-Digital Video Cassette Recorder (HD-DVCR) Conference defines a command set which is called AV/C CTS (Audio/Video Control Command and Transaction Set) so that an operation command from a remote controller is transferred to a target control device (called “local device”) via the IEEE 1394 serial bus. Here, the IEEE 1394 serial bus is a standard related to the high-speed data transfer, which is defined by the Institute of Electrical & Electronics Engineers (IEEE). The IEEE 1394 serial bus is used as an interface for connecting each device of a digital multi-media system, having an isochronous transfer mode and an asynchronous transfer mode. Here, A/V data is transferred in real time using the isochronous transfer mode, and transactions required for communication, including read, write and lock, are transferred in an asynchronous pattern using the asynchronous transfer mode. Also, control commands such as AV/C CTS are transferred in an asynchronous pattern using the asynchronous transfer mode.
However, the contents defined by AV/C CTS include commands relating to a direct/indirect user's input button, but commands relating to all operations are not completed yet, and are still being updated. Furthermore, commands related to the transfer of information which is not noticed by a user, or the notice of which is not necessary, are not yet provided. Thus, it is difficult to achieve a single common remote control for all devices.
On the other hand, according to the articles entitled “Specification of Consumer-Use Digital VCRs using 6.3 mm magnetic tapes-Part 8: ATV Specifications of Consumer-Use Digital VCR” and “Specification of Digital Interface for Consumer Electronic Audio/Video Equipment-Parts 1 & 4”, which are published by the HD-DVCR Conference, it is prescribed that an advanced television (ATV) signal having MPEG2-TS (Moving Picture Experts Group 2-Transport Stream) which is transferred using the IEEE 1394 can be recorded by an HD-VCR using 6.3 mm magnetic tape. In particular, it is prescribed to transfer the MPEG2-TS using the isochronous transfer mode of the IEEE 1394 while having a common format, i.e., common isochronous packet (CIP) header structure as in the case of a digital video cassette (DVC) called a camcoder. Here, the AV/C CTS is adopted as a control command. Also, the MPEG2 is roughly classified into one of three: MPEG2-system, MPEG2-video and MPEG2-audio. A transport stream (TS) and a program stream (PS) are defined as a transfer standard in the MPEG2-system.
FIG. 1 shows a typical example of data transfer between the ATV and HD-VCR. According to the definition by [1] “Blue Book”, published by the HD-DVCR Conference, including articles entitled “Specification of Consumer-Use Digital VCRs using 6.3 mm magnetic tapes”, “Specification of Digital Interface for Consumer Electronic Audio/Video Equipment”, and “Specifications of A/C Command and Transaction Set for Digital Interface”, A/V data transferred from an ATV 10 to HD-VCR 20 which are connected by an IEEE 1394 cable 30 during a recording mode, is a multi-program MPEG2-TS, and data transferred from the HD-VCR 20 to the ATV 10 during a playback mode is a single program MPEG2-TS. Here, the term ATV refers to the American high definition television (HDTV) suggested by the Advanced Television Systems Committee (ATSC). Also, the AV/C CTS suggested in the Blue Book defines control commands with respect to VCR sub-devices, most of which relate to mechanical operation.
For example, commands from a remote controller 11 for the ATV 10, such as fast-forward and rewind, can be transferred to the HD-VCR 20 via the IEEE 1394 serial bus. However, control commands to the VCR sub-devices do not include commands for transferring information related to an MPEG2 system layer, e.g., program number.
Thus, the MPEG2-TS is transferred from the ATV 10 to the HD-VCR 20 during the recording mode. Here, the HD-VCR 20 should receive information required for parsing the MPEG2-TS being transferred from the ATV 10, from a user using a remote controller 21 for HD-VCR 20.
Also, the recorded single program MPEG2-TS is transferred from the HD-VCR 20 to the ATV 10 during the playback mode. Here, a program number recorded in a video auxiliary (VAUX) region should be transferred from the HD-VCR 20 to the ATV. Additionally, it is prescribed in the Blue Book to record the program number in the VAUX region of a tape.
However, the multi-media system of FIG. 1 requires a separate remote controller for each device connected to the ATV. That is, when a plurality of devices, being capable of recording/reproducing a received signal, are connected to the ATV, there is an inconvenience in that an operational command should be input to each recording/reproducing device by the user, using a different remote controller for each device.
Also, when selecting a program by parsing a program guide information (PG) for the MPEG2-TS in the multi-media system shown in FIG. 1, the HD-VCR 20 should first parse the program guide information in the multi-program MPEG2-TS transferred from the ATV. In order to display the parsed program guide information on an on-screen graphic (OSG) display, the OSG of the program guide information is transferred to the ATV 10 by being MPEG2-TS encoded since there is no OSG transfer standard in the IEEE 1394. Then, a user can input a program number corresponding to an intended program, using an up/down key of the remote controller 21 for the HD-VCR while viewing the OSG displayed on the ATV 10. Thus, this multi-media system requires an extra encoding circuit in the HD-VCR 20, for the MPEG2-TS encoding of the OSG, and the ability to parse the program guide information from MPEG2-TS in order to constitute the OSG. Also, the generation of the OSG is dependent on the VCR manufacturer, so it is difficult to provide the same OSG consistently. Although the ATV parses the program guide information in transferred MPEG2-TS and displays the parsed program guide information on an OSG display, and a user inputs a program number using the remote controller 11 for the ATV, the program number can not be transferred to the HD-VCR 20, since no command is defined for transferring the program number to the HD-VCR 20.